With the growing abundance of natural gas, there has been a tendency in the engine industry to modify existing diesel engines or create new dual fuel engines with the capability of burning both natural gas and distillate diesel fuel. When operating in a dual fuel mode, a gaseous fuel charge is supplied to the engine cylinder by moving gaseous fuel through a metering valve and a gas supply nozzle into the engine cylinder. The gaseous fuel charge may then be ignited by compression igniting diesel fuel directly injected into the injection cylinder. When operating in a single fuel mode, the engine operates with only diesel fuel. Especially when the engine is operating in a diesel fuel mode, there may be a risk of back flow of gases and contaminants from the engine cylinder back toward the gas metering valve. These issues may be further exacerbated in the case of dual fuel two stroke engines of the type sometimes utilized in the locomotive industry.
The present disclosure is directed toward one or more of the problems set forth above.